Study objectives: Several studies have reported psychiatric comorbidity in patients with narcolepsy type 1 (NC1). The primary aim of this study was to explore the extent of psychiatric symptoms in a cohort of Norwegian NC1 patients, most of whom were H1N1-vaccinated. We also wanted to explore possible causes of the psychiatric symptoms seen in NC1.

Methods: Cross-sectional study. Psychiatric symptoms were assessed by the Achenbach System of Empirically Based Assessment (ASEBA) Child Behavior Check List (CBCL) in children and by Adult Self Report (ASR) in adults.

Results: The mean (SD) total T-scores were 58.6 (9.2) for children and 57.0 (9.8) for adults, these being mainly driven by internalizing problems. Internalizing symptom T-scores showed that 37.5% of the children and 33.3% of the adults were in the clinical range of concern. T-scores were lower when the questionnaire's sleep-related items were excluded. However, 27.5% of children and 22.2% of adults still remained within the total psychiatric symptoms clinical range. Psychiatric symptoms and excessive daytime sleepiness were not associated. However, in children fragmented sleep, measured by sleep-stage shift index was significantly negatively associated with all the psychiatric summary scores (all p ≤ 0.020), and awakening index was negatively associated with externalizing (p = 0.042) and total summary scores (p = 0.042). In adults, awakening index, but not sleep-stage shift index, was positively associated with internalizing score (p = 0.015). Hypocretin-1 levels showed no association with psychiatric symptoms.

Conclusions: We found a high prevalence of psychiatric symptoms in NC1 patients. Fragmented sleep was significantly associated with psychiatric symptoms.